Vaisala PTB200 - Manual (Page 9)

PTB 200 8 (28)
Digital Barometers
SSD/Operating Manual 24th February 1993 PTB200-O0284-1.1
The pulse frequency is about 4.5 kHz at baud rate 9600. The pulse
output is triggered using a positive pulse (e.g. 100 ms/5 VDC). The
pulse output voltage levels can be either RS 232C levels or TTL levels.
The selection is made with a jumper (Fig. 5).
The pressure resolution is limited in the pulse output mode to 0.1 hPa.
Each pulse represents 0.1 hPa, e.g. 10000 pulses equal 1000.0 hPa.
2.6 Pressure connections
The barometer is equipped with a standard Clippard barbed pressure
fitting with 10-32 external thread installed in the barometer. This fitting
is ideal for an 1/8" internal diameter tubing.
If some other pressure fitting needs to be used, it is possible to replace
the barbed fitting. The pressure connection in the barometer housing
has a metric M5 internal thread which is in practice compatible with
non-metric 10-32 internal thread.
The barbed pressure fitting is not recommended for turbulent or high
speed static wind conditions: the accuracy quoted for the PTB 200
digital barometers does not include any wind effects.
The PTB 200 barometers are designed to measure the pressure of
clean, non-condensating, non-conducting and non-corrosive gases
only.